Artificial teeth



Aug. 21, 1928. I 1,681,436 v v. H. SEARS A ARTIFICIAL i'sarn Filed April 9, 1927 ATTORNEYfi,

Patented Aug. 21, 1928.

UNITED STATES VICTOR H. SEARS, OF NEW YORK, .N. Y.

ARTIFICIAL TEETH.

Application filed April 9,

This invention relates in general to artificial teeth and more particularly to dentures including sets of artificial teeth for both the upper and the lower jaws.

Artificial teeth are known not to function efficiently in dentures, particularly dental plates, because of the instability of the artificial teeth in the month which makes it practically impossible for the occlusal surfaces 1 of the teeth to cooperate in a grinding opera.-

tion like that possible with natural teeth.

Furthermore, great uneasiness is encountered by most wearersof dental plates in frequent slipping or rubbing on the ridges or gums or displacement of the plates when the teeth are brought together which causes soreness in the mouth as well as annoyance and difliculty in chewing food, etc.

. Most artificial teeth are made in close simulation of natural teeth, and I am satisfied that the troubles above mentioned are largely due to the formation or shape of such artificial teeth made in simulation of natural teeth,

particularly the last four back teeth on each side ofeach jaw, that is, thefour molars and the-four bicuspids on each jaw. The cusps and the occlusal surfaces of such teeth on the lower jaw interlock with the, cusps of the teeth on the upper-jaw and revent relative movement of the plates bot sidewise and forwardly and backwardly in the mouth.

The consequence is that when pressure is exerted b; the jaws either laterally or forwardly and backwardly, the upperor the lower or both of the plates slide relatively to the respective jaws or tilt'due to the necessarily unstable mounting of the plates on the gums or ridges.

One ob'ect of my invention is to provide a 40' new form of artificial teeth for the upper and lower jaws which have their occlusal surfaces so designed that free and easy relative lateral and back and forth movement of the dentures is permitted and interlocking of the teeth prevented, so that all forces exerted by move ment of the jaws uponthe plates and which might tend to cause shding of the dentures upon the gums or ridges or tilting thereof,

are so reduced, dissipated or translated as to revent such sliding or tilting of the dentures. n other words, my invention provides teeth which make the late or dentures more easily slidable relatively to each other. than to the gums or on which they. are

56 mounted. r

1927. Serial No. 182,399.

Another object is to provide artificial teeth having a novel and improved form of occlusal surface wherebysuch relative sliding of the plates is permitted and also the cutting or grinding of food may be eiiiciently accomplished.

Other objects are toprovide dentures including upper and lower plates 'wherein the molars or posterior teeth in one plate have grooves on their occlusal surfaces to cooperate With ridges on the occlusal surfaces of the corresponding teeth in the other plate in such a manner that the plates may freely slide uponcach other hack and forth longitudi' nally of the grooves and ridges and slide laterally transversely of said grooves and said ridges, said ridges normally fitting into said grooves when the jaws are closed; to provide such dentures wherein the sides of said grooves are formed with alternate projections and recesses with which'coope-rate said ridges in cutting and grinding or mashing food, and to-obtain other results and advantages as are brought out in the following description. 1

Referring to the accompanying drawings, in which corresponding and like parts are designated throughoutthe several views by the same reference characters,

Figure 1 is a side elevation of dentures or plates for the upper and lower jawsembo dying my invention;

Figure 2-is a perspective view of the lower denture showingin more detail the construction of the teeth embodying my invention; I

Figure 3 isa fragmentary perspective view of the rear end of one side of the upper plate, looking at the same from beneath;

Figure 4 is a transverse vertical sectional view, taken on the line 4-4 of Figure 1;

Figure 5 is a composite perspective view of one of the upper anterior molars and one of the lower anterior molars, and

Figure 6 is a plan 'view of the rear of one side of the upper plate showing in more detail the grooves in the four molars.

While I have illustr ated complete upper .and lower sets of teeth, my invention is particularly directed toward improvement of the rear ends of the dentures and the bicuspid and molar teeth for the upper and lower jaws.

In its broadest aspect my invention consists in forming grooves in the occlusal surfaces of the upper molar teeth which are adapted to receive ridges on the occlusal surfaces of the lower molar teeth, the grooves and ridges extending from front to rear of the jaws and freely permitting back and forth and lateral relative movement of the upper and lower dentures. Preferably the grooves and ridges have inclined sides substantially the whole of each of which is in one plane to facilitate the relative sliding of the dentures. While I have shown the molars as separate teeth, it is to be understood that my invention may also be embodied in block form of teeth, that is, where the posterior and anterior molars are made in one piece as are also the premolars or bicuspids.

More specifically describing the lower (lent'ure A, the reference characters 1 designate the anterior molars, 2 the posterior molars, 3 the posterior bicuspid and 4 the anterior bicuspid. The occlusal surface of the anterior molar is composed of two substantially fiat downwardly diverging inclined sides 5 and 6 which meet in a ridge 7 extending from front to rear of the tooth and substantially centrally thereof. The posterior and the anterior bicuspids 3 and 1 are similarly formed with ridges 8 and 9, and these ridges are in substantial alinement with the ridge 7 from front to rear of the denture and their sides are in substantially the same planes of the sides 5 and 6 of the ridge 7. The posterior molar 2 is somewhat different in form from the anterior molar 1. in that the occlusal surface thereof is composed of a substantially horizontal surface 10 which extends from substantially the plane of the ridge 7 toward the rear end of the denture, said surface being disposed at an angle to a surface 11 which is in substantially theplane of the surface 6 of the ridge 7. Another surface 12 meets the surface 10 and is in substantially the same plane as the surface 5 of the anterior molar. This formation provides an apex or point 18 at the anterior side of the molar 2 which is disposed in substantially the same plane and in alinement with the ridge 7.

Now coming to the upper denture B, the

, reference character 14 designates the anterior molar, 15 the posterior molar and 16 and 17 the posterior and anterior bicuspids, respectively. The anterior molar 14 has its 'occlusal surface composed of two inclined downwardly diverging surfaces 18 and 19 which are at substantially the same angle as the surfaces 5 and 6 of the anterior lower molar 1, but these surfaces meet in a substantially straight and horizontal portion 20 which substantially corresponds to the top of the ridge 7. Obviously the surfaces 18, 19 and 20 form a groove, and this groove extends from frontto rear of the denture so as to receive the ridge 7. The posterior upper molar 15 is formed with a similar groove 21, but preferably the angle formed by the plane of the portion 20 with the plane 19 is slightly I wider or more obtuse than that of the groove in the anterior molar 14. The bicuspids 1' and 17 are formed with grooves 22 which or in substantial alinemcnt from front to bacl of the jaw with the groove in the anterio molar and have their inclined sides in sub stantially the same planes as the sides 18 am 19 of the anterior molar. Each of the pos tcrior molars 15 and the bicuspids 1G and 1 also have fiat portions at the bases of'th grooves corresponding to and in alinemcn with the surface 20 of the anterior molar.

With teeth so constructed and .properl; mounted in the upper and the lower plate: it will be observed that the upper molars ma freely slide relatively to the lower molar back and forth by contact, of the incline sides of the grooves and ridges, and free rel ative lateral movement of the dentures i possible by relative sliding of the surfaces 0 the ridges and the grooves. This action ma be more easily understood from reference t Figure 4 of the drawings. The flat portion at the bases of the grooves in the upper inc lars also permit limited relative lateral movt ment' of the dentures so that they may h comfortably adjusted to each other in occll' sal position. In other words, there is no IJUE sibility of the upper molars and the lowc molars interlocking with each other as is th case when the teeth conform to the natur: formation of the occlusal surfaces where ll: cusps of the upper and lower teeth intcrloc with each othen With reference to Figure it will be obvious that the grinding or cuttin of food may take place by relative slidin action of the outer or buccal surfaces 6 of fl ridges and the corresponding surface 18 the grooves, and the mashing or crushing the food after it has been so cut or shredde takes place between the lingual surface 5 the ridge and the corresponding surface 1 of the groove in the upper denture.

To facilitate cutting, shredding and mast cation of food, the buccal surfaces of the u per molars, for example the surface 18, :11 formed with saw-tooth shaped projections which have their pointed ends directed dowi wardly and between which are formed c'orr spondingly shaped but reversed recesses Q The buccal surfaces of the ridges of the low molars, for example the surface 6, are fornn with grooves 26 extending from front to rea that is.v at substantially right angles to tl projections 23. With this construction, will be clear that the inclined edges 27 of tl projections 23 will cooperate with the edg of the grooves 26 in cutting, tearing or shre ding food, and the inclined sides of tl projections 23 will direct the food into 11 bases of the grooves where the food will i caught between the lingual surfaces of tl upper and lower teeth, for example the su faces 5 and 19, and by them mashed i crushed. The grooves in the upper mola 14--17 may be of the same width, but pre erably the grooves gradually widen from the posterior molar to the anterior bicuspid 17, as clearly shown in Figure 6 of the drawing. This is to accommodate the somewhat greater lateral movement of the jaws toward the forward points thereof as contrasted with the movements at the pivotal points.

The obtuse angle of the grooves in the upis no contact between the upper and lower molars which might cause tilting or lateral displacement of the plates. Furthermore, the

particular formation of the upper or occlusal surface of the posterior lower molars admits of the tooth being moved forwardly or rearwardly and the apex may enter the groove of the anterior upper molar if necessary, to meet different conditions.

Further, it will be noted that the inside or lingual cusps of the lower molars are cut away entirely and that theoutside or buccal cusps are cut away on an inwardly and upwardly inclined plane so that there is no possibility of the tongue getting beneath projections on the lower teeth and lifting the plate.

While I have shown the now preferred embodiment of my invention, it will be understood that this is primarily for the purpose of illustrating the principles of the invention and that many modifications and changes may be made in the details of construction of the contours of artificial teeth without de parting from the spirit 'or scope of the invention. Therefore, I do not desire to be understood as limiting myself except as required by the following claims when construed in the light of the prior art.

Lclaim is 1. In dentures, a lower set of molar teeth having their occlusal surfaces in the formof ridges extending in front to rear direction and having downwardly receding oppositely inclined surf ces, and an upper set of molars having their occlusal surfaces in the form of grooves substantially corresponding in crosssectional shape to said rid es and extending in the same direction, said ridges entering said grooves when the upper and lbwer, teeth are in occlusal position and permitting free rela-r tive sliding of the upper and lower teeth back and forth and laterally, one side of said grooves having projections to cooperatewith said ridges in cutting, shredding or tearing food.

2. In dentures, a lower set of molar'teeth ridges having cooperatingprojections and recesses the edges of which upon contact due to masticating movement of the jaws serve to cut, shred or tear food.

3. In dentures, a lower set of molar teeth having their occlusal surfaces in the form of ridges extending in front to rear direction and having downwardly receding oppositely inclined surfaces, and an upper set of molars having their occlusal surfaces in the form of grooves substantially corresponding in cross sectional shape to said ridges and extending in the sa1'ne direction, said ridges entering said grooves when the upper and lower teeth are iniocclusal position and permitting free relative sliding of the upper and lower teeth back and. forth and laterally, one side of said grooves having saw-tooth shaped projections with the points directed downwardly and recesses between them to cooperate with said" ridges in cutting, shredding or tearing food.

4. In dentures, an upper set of molars having their masticating surfaces in the form of.

grooves extending from front to rear and having oppositely inclined sides downwardly diverging and from a substantially flat horizontal bottom portion, and a lower set of molars having their masticating surfaces in the form of ridges having oppositely inclined and downwardly diverging sides corresponding-to said grooves, said ridges entering said grooves when the upper and lower teeth are I g i in occlusal'position and permitting free rela- Having thus descr bed the 1nvent1on, what a of lateral play or movement of the dentures without vertical movement.

5. In dentures, a lower set ofmolar teetli having their occlusalsurfaces in the form of ridges, extending in front to rear direction and having downwardly receding oppositely inclined surfaces,a nd an upper set of molars having their occlusal surfaces in the form of grooves substantially corresponding in crosssectional shape to, said ridges and extending in the same direction, said ridges entering said grooves when the upper and lower teeth are in occlusal position and permitting free relative sliding of the upper and lower teeth back and forth and laterally, said grooves gradually increasing in width from the rear to the front to compensate for differences in the extent of natural lateral movement of the jaws forwardly from the pivotal point. 6. In dentures, a lower set of molar teeth having their occlusal surfaces in the form of ridges extending in front to rear direction and having downwardly receding oppositely inclined surfaces, and an upper set of molars having their occlusal surfaces in the form of grooves substantially corresponding in crosssectional shape to said ridges and extending in the same direction, said ridges entering 'said grooves when the upper and lower teeth are in occlusal position and permitting free relative sliding of the upper and lower teeth back and forth and laterally, the groove in the posterior upper molar being more obtuse than the grooves in the other upper teeth to prevent contact between them in all but one position, to obviate tilting or lateral displacement of the dentures.

7. In dentures, a lower set of molar teeth having their occlusal surfaces in the form of ridges extending infront to rear direction and having downwardly receding oppositely inclined surfaces, and an upper set of molars having their occlusal surfaces in the form of grooves substantially corresponding in crosssectional shape to said ridges and extending in the same direction, said ridges entering said grooves when the upper and lower teeth are in occlusal position and permitting free relative sliding of the upper and lower teeth back and forth and laterally, the posterior lower molar having the rear of its occlusal surface rearwardly receding in a substantially horizontal plane.

8. In dentures, a lower set of molar teeth, each tooth having on its masticating surface 49 a single ridge having downwardly receding oppositely inclined sides which meet the respective buccal and lingual sides of the teeth andare in substantial alinement from front to rear of the jaw with the ridges of adjacent teeth, and an upper set of teeth, each tooth having a single groove with inclined sides in alinement from front to rear of the jaw with the grooves of adjacent teeth to embrace said ridges of the teeth on the lower jaw when the upper set and the lower set of teeth are in occlusal position, whereby said upper set and said lower set may relatively freely slide from front to back and laterally.

9. In dentures, a lower set of molar teeth, each tooth having on its masticating surface a single ridge having downwardly receding oppositely inclined sides which meet the respective buccal and lingual sides of the teeth and are in substantial alintanent from front to rear of the jaw with the ridges of adjacent teeth, and an upper set of teeth, each tooth having a single groove, formed with a flat horizontal bottom and flat sides diverging downwardly from said bottom and in alinc- Inent from front to rear of the jaw with the grooves of adjacent teeth to embrace said ridges of the teeth on the lower jaw when the upper and lower set of teeth are in occlusal position, whereby said upper set and said lower set may relatively freely slide from front to back and laterally.

10. An artificial molar tooth having its occlusal surface composed of two converging flat sides which meet in a ridge on the longitudinal center line of the tooth and extend respectively from the lingual and the buccal sides of the tooth.

11. An artificial molar tooth having on its occlusal surface a single longitudinal groove formed of two flat sides converging respectively from the lingual and the buccal sides of the tooth toward the longitudinal center thereof, one of said sides having a plurality of projections providing cutting edges transverse of the plane of said side.

12. The artificial tooth set forth in claim 11 wherein said cutting edges are inclined to the longitudinal center line of the tooth and extend from the edges of the tooth to the bottom of said groove.

VICTOR H. SEARS. 

